Yet the discordance patterns are consistent with past accelerated radioisotope decay, which would also render these "clocks" useless.
Thus there is no reliable evidence to dispute that these metamorphosed basalt lava flows deep in Grand Canyon date back to the Creation Week only thousands of years ago.
The computer program Isoplot was used to plot isochrons and calculate isochron ages from the other radioisotope analyses.
Even when the calculated error margins are taken into account the different radioisotope dating methods yield completely different "ages" that cannot be reconciled—1240±84 Ma (Rb-Sr), 1655±40 Ma (Sm-Nd), and 1883±53 Ma (Pb-Pb) (see diagram).
None of the obtained isochron "ages" corresponds to the "date" for any recognized event, neither the original lava eruptions nor the subsequent metamorphism.
These included seven samples from a 150 meter long and 2 meter wide amphibolite body outcropping just upstream from the mouth of Clear Creek at river mile 84 (measured from Lees Ferry).
All 27 samples were sent to two well-credentialed internationally-recognized, commercial laboratories for radioisotope analyses—potassium-argon (K-Ar) at a Canadian laboratory, and rubidium-strontium (Rb-Sr), samarium-neodymium (Sm-Nd), and lead-lead (Pb-Pb), at an Australian laboratory.
Furthermore, the seven samples from the small amphibolite unit near Clear Creek, which should all be the same age because they belong to the same metamorphosed basalt lava flow, yielded K-Ar model ages ranging from 1060.4±28 Ma to 2574.2±73 Ma.
This includes two samples only 0.84 meters apart that yielded K-Ar model ages of 1205.3±.2±73 Ma.
Metamorphic rocks are not always easy to date using radio-isotopes.
Results obtained usually signify the "date" of the metamorphism, but they may also yield the "age" of the original volcanic (or sedimentary) rock.
The most widely known form of radiometric dating is carbon-14 dating.
This is what archaeologists use to determine the age of human-made artifacts. The half-life of carbon-14 is only 5,730 years, so carbon-14 dating is only effective on samples that are less than 50,000 years old.
Both laboratories use standard, best-practice procedures on state-of-the-art equipment.